When electrical building wiring is electrically connected to electrical supply wiring, it is typically done through circuit breakers to limit electrical current overloads on the building wiring. The electrical connections are typically made by way of screws on the circuit breakers. In order to perform the installation, the installer must first strip the insulation off from the electrical wiring to expose the inner copper conductor. The inner conductor is then inserted under the screw and it is then screwed down tightly to secure the conductor on the circuit breaker.
Electrical circuit breakers are physically mounted into an electrical distribution panel and electrically connected to current-carrying electrical wires usually made of copper conductors insulated with thermoplastic material. The procedure to make the electrical and physical connection involves: removal of the insulating material to expose the copper conductor, straightening the copper conductor, loosening the screw on the circuit breaker, placing the copper conductor under the screw head on the circuit breaker, and tightening the screw to compress the copper conductor under the screw head.
Care must be exercised in each of these steps to insure a good electrical and physical connection. The insulating material must be removed in a manner as not to nick or cut the copper conductor, because nicking or cutting the copper conductor weakens the mechanical strength of the conductor and also creates a local spot of increased electrical resistance because of the copper material being removed. This local spot of increased resistance will result in a local hot spot in temperature as electrical current flows through the conductor. Also, it is critical to the electrical connection to make sure that none of the insulating material is caught between the screw and the circuit breaker. Having the insulative material captive under the screw decreases the terminating force that can be applied to the conductor and thereby increases the electrical resistance of the connection. The screw must be made tight in order to provide the best electrical connection, but over-tightening the screw will strip the threads of the screw or the threads of the circuit breaker, resulting in a poor electrical connection.
Increases in resistance, caused by poor connections as described above, result in increases in temperature during current flow. This situation could lead to the ignition of flammable materials that are within close proximity.
U.S. Pat. No. 5,006,077 discloses telescoped metal cylinders with one of the metal cylinders being rotatable relative to the other of the metal cylinders by means of a dielectric actuator secured to the rotatable metal cylinder in order to terminate an electrical wire in an insulation-displacement slot.
U.S. Pat. No. 5,496,192 discloses a similar insulation-displacement connector with stacked cylindrical insulation-displacement contacts that terminate electrical wires in insulation-displacement slots thereof by movable dielectric actuators.
The insulation-displacement connectors of these patents are used to interconnect telephone lines and not in connection with circuit breaker switch mechanisms.